Overall,the most balanced one for me is Stanly. 8/8 and attack manip so strong that nullifies montana, he would only have a hard time against Vickie, Lyse Teria and Edd. If it's T2 or something like that, just use all 3 of them. If it's Elo, go for Stanly.
Depends on your play style. Stanly is a bit predictable and has a difficult ability to activate. Lulabee is a bit more stable she guarantees her 9 power and removes the pesky bonuses. Stanly on the other hand is a game changer 8 damage is great and can win you the game single handedly. People generally use Oraya or Stanly in Elo, Oraya gives you 10 gap which is insane.
I don't playe ELO, and I can only answer for the Duel mode. In this mode, you should definitely be wary of Oraya, Kate will be very likely to play her first and make her ability work to create a big life gap. I lost to many of her Ulu Watu decks because of Oraya (I play Skeelz BTW)